Selecting clutch responsive to direction of rotation



Aug. .31, 1954 D. NELSON ERAL SELECTING CLUTCH RESPONSIVE T0 DIRECTIONOF ROTATION Filed May 11, 1953 2 2 i 0 m 0 B R J 5 M f. I 2 w 1% x gINVENTORS' D. Q Ale/sen 6. E. Wall/garb? BY I ATTORNEY Patented Aug. 31,1954 SELECTING CLUTCH RESPONSIVE TO DIRECTION OF ROTATION Donald 0.Nelson, Los Angeles, and Clare E. Wallquist, Burbank, Calif assignors toBendix Aviation Corporation, North Hollywood, Calif., a

corporation of Delaware Application May 11, 1953, Serial No. 354,364

6 Claims. (01. 74-412) rotation of the input shaft.

An object of the invention is to provide a sim- In the drawing: i

Fig. 1 is a longitudinal section through a gear box in accordance withthe invention;

Fig. 2 is a detail section taken in the plane IIII of Fig. 1;

Fig. 3 is a detail plan view taken in the plane III-.III of Fig. 2;

Fig. 4 is a detail sectional view taken in the plane IV--IV of Fig. 2;

Fig. 5 is a detail plan View similarto Fig. 3 but showing a modifiedconstruction;

Fig. 6 is a detail view similar to Figs. 3 and 5 but showing a secondmodified construction; and Fig. 7 is a view taken in the plane VII-VIIof F 6. i

Referring to Fig. l, the gear box therein disclosed comprises a casing[0 having an input or 10 and carrying a second gear which meshesrotation therewith.

Shaft I1 is also pinned to a gear 25 that meshes with a gear 26 on theoutput shaft l2.

It will be observed that if the clutch drive member I6 is connected tothe driven member 24,

the input shaft II drives the output shaft [2 through a relatively smallspeedv reduction through the gears l3, I4, 25 and 26 respectively, andtwo reversals of direction are produced so that the output shaft I 2rotates in the same direction as the input shaft II.

On the other hand, when the clutch driving member 22 is connected to theclutch driven member 24, the shaft H drives the shaft l2 through thegears l3, l5, 20,2|, 25 and 26, producing a relatively large speedreduction. Furthermore, since there are three reversals of direction theoutput shaft l2 rotates in direction opposite to that of the input shaftI].

As shown in Figs. 1, 2,3, and 4, the clutch drive members 16 and 22 havejuxtaposed end faces 30 and 3| respectively, each of which has: axiallyextending groove-like recesses 32. The drive members ltand 22 aremaintained in separated pair of pawls 36 and 31, which pawls are adaptedto engage the recesses 32 in one or the other of the faces 30, 31 toeffect the driving connection.

The pawls 36 and 31.1ie approximately in a plane perpendicular to theradius from the shaft ment of cooperating shoulders eta and 3711 on poseto be hereinafter explained.

The mechanism so far described functions as follows: Let it be assumedthat the shaft M is I that the clutch drive member 22 secured to thegear 2| rotates in the same direction as the shaft As shown in Fig. 1this causes one of the recesses 32 in the face 3| of member 22 to engagethe pawl 31 and thereby drive the driven clutch member 24, the shaft l1,and the gear 25 with the gear 2|. This causes the shaft i2 to rotate indirection opposite to the shaft as'indicated by the arrow. At this timethe other clutch driving member I6 is rotating in the oppositedirection, but this does not affect the drive because the pawl 36 ispositioned clear of the face 30 of the clutch drive member l6.

Now let it be assumed that the motor 58 is reversed to thereby reversethe direction of rotation of the input shaft H and all of the gears andshafts permanently coupled thereto. The reversal of the clutch drivemember 22 disengages the pawl 3i from the recess 32 in the face 31 andcauses it to ride onto the face 3|. This rocks the pawls 35 and 31 as aunit about the pivot screw 35 until the pawl 36 bears against the face30 of the other clutch drive member IE. Final movement of the pawl 37out of the recess 32 contracts the pawls 36 and 31 toward each other,separating the abutting shoulders 36a and 31a, and deflecting the spring48. Since the clutch drive memher it reversed its directionsimultaneously with the reversal of the member 22, it now moves in suchdirection as to cause the pawl 3% to drop into and engage one of therecesses 32 in the face 3|), thereby rotating the pawl unit and theclutch driven member 24 with it to rotate the output shaft |2 at ahigher speed (relative to the speed of the input shaft I!) than before.However, since the clutch driven member 24 is always driven in the samedirection irrespective of which of the clutch drive members It or 22drives it, the output shaft l2 runs in the same direction as before.

The mechanism described is quiet in operation because whenever one ofthe pawls 36 or 31 is engaged in driving relation with its associateddrive member it or 22, the other pawl is held clear of its associatedface. This results from the fact that the spacing between the pawls intheir expanded position exceeds'the spacing between the faces 36 and 3|by a distance less than the depth of the recesses 32.

Various departures from the exact construction shown in Figs. 1 to 4inclusive may be made while still obtaining the advantages of the.invention. Two such modifications are shown in Fig. 5 and in Figs. 6and '2' respectively.

Fig. 5 shows a very simple arrangement in which the ends M1?) and 400 ofthe spring 40 themselves constitute the pawls. With this arrangement itis desirable to make the driving edges or faces 32a of the recesses 32reentrant so that when the end sec or 400 of the spring is engaged inthe recess, it is carried to the bottom thereof to thereby positivelycarry the other spring end clear of its associated face.

In the modification shown in Figs. 6 and 7- the pawls are constituted byleaf-spring elements 5% and Si respectively. Thus as shown in Fig. '7the element at comprises a central portion 62 and three arm portions itwhich extend in a generally arcuate direction. Each arm portion 63constitutes a resilient leaf spring element which is sethe leaf -springcured at one end to the central portion 62, the latter being secured asby rivets 64 to the end face of a flange 2M on the driven hub member 24.The leaf spring element 63 of each of the elements iili and 5| isprestressed to press against its opposite leaf on the other memberthrough a portion of its length, and at its outer end diverges from theother element to form ends 65 which constitute the pawls. As shown inFigs. 6 and '7 there are three of the resilient leaf spring elementsprovided symmetrically distributed about the axi of rotation. Howeverthis is not essential, and if desired a lesser number may be employed.

The structure of Figs. 6 and 7 functions similarly to that of Fig, 5.The outer ends 65 of elements, which constitute the pawls, are spacedapart a distance greater than the spacing between thefaces 3t and 3| byan amount less than the depth of the recesses so that, as shown in Fig.6, when one pawl is en-' gaged in a recess, its opposite pawl is heldclear of its associated face.

Summarizing, it will be observed that in all of the embodimentsillustrated, the invention resides in the combination of the followingelements:

A. A pair of rotatably supported spaced coaxial drive members It and 22having juxtaposed end faces 35! and 3| containing radial recesses 32.

B. Means for selectively rotating each drive member in either directionand simultaneously rotating the other drive member in the oppositedirection, which includes the gears l3, l4, I5, 20, and 2|.

C. A rotary driven member 24 coaxial with and positioned between the endfaces 30 and 3| of the drive members It and 22.

D. A pawl unit comprises two diverging pawls (3B and 31 in Fig. 1, laband we in Fig. 5, and E5, 65 in "Fig. 6) symmetrically positionedbetween the end faces 38 and 3| approximately in a plane perpendicularto a radius from the axis with one pawl adjacent one face and the otherpawl adjacent the other face, and means (25 in Figs. 1 and 5, and 53 inFigs. 6 and 7) supporting the pawls on the driven member for rotarymovement therewith and swinging movement relative portion Ma of thespring in Fig. 5, and the portion 63 of the leaf springs in Fig. 7)yieldably supporting said pawls with respect to each other for movementbetween a distorted contracted position in which they are spacedapart'a'distance equal to the spacing between the faces 38 and 3| and anormal expanded position in which they are spaced apart a distanceexceeding the spacing between the faces ti! and 3| by an amount lessthan the depth of the recesses 32 whereby engagement of either pawl in arecess of the adjacent face holds the other pawl clear of its adjacentface and disengagement of either pawl from a recess urges the other pawlagainst itsadjacent face for engagement in a recess therein in responseto rotation of that face.

Although for the purpose of explaining the invention, a particularembodiment thereof has been shown and described, obvious modificationswill occur to a person skilled in the art, and we do not desire to belimited to the exact details shown and described.

We claim:

1. A mechanism of the type described com-.,

prising: a pair of rotatably supported, spaced, coaxial drive membershaving juxtaposed end faces containing radial recesses; means forselectively rotating each drive member in either direction andsimultaneously rotating the other drive member in the oppositedirection; a rotary driven member coaxial with and positioned betweensaid end faces of said drive members; a pawl unit comprising twodiverging pawls symmetrically positioned between said end facesapproximately in a plane perpendicular to a radius from said axis withone pawl adjacent one face and the other pawl adjacent the other face,and means supporting said pawls on said driven member for rotarymovement therewith and swinging movement relative thereto toward andaway from their adjacent faces; means yieldably supporting said pawlswith respect to each other for movement between a distorted, contractedposition in which they are spaced apart a distance equal to the spacingbetween said faces and a normal, expanded position in which they arespaced apart a distance exceeding said spacing between said faces by anamount less than the depth of said recesses, whereby engagement ofeither pawl in a recess of the adjacent face holds the other pawl clearof its adjacent face, and disengagement of either pawl from a recessurges the other pawl against its adjacent face for engagement in arecess therein in response to rotation of that face.

2. A mechanism according to claim 1 in which said means supporting saidpawls on said driven member comprises pivot means extending radiallyfrom said driven member and pivotally engaging said pawls.

3. A mechanism according to claim 2 in which said means yieldablysupporting said pawls with respect to each other comprises cooperatingabutting shoulders on said respective pawls limiting divergence thereofto said normal expanded position, and spring means urging said pawlstoward said expanded position.

4. A mechanism according to claim 2 including a wirespring meanscomprising a helical portion encircling said pivot means and end portionextending substantially radially from said helical portion, said endportion constituting said pawls and said helical portion constitutingsaid means for yieldably supporting said pawls with respect to eachother.

5. A mechanism according to claim 1 in which said pawls and said meanssupporting said pawls consist of a pair of resilient leaf springelements secured to and extending from said driven member, said elementshaving supporting portions secured together in side-by-side relation andpawl portions diverging from each other.

i 6. A mechanism according to claim 1 in which said recesses havere-entrant side walls facing the ends of said pawls whereby engagementof a pawl with a recess guides the end of the pawl to the bottom of therecess.

No references cited.

